With the expansion of data center services, virtualization has become popular. Virtualization technologies mainly include network virtualization, storage virtualization and server virtualization. For server virtualization, a physical server can host multiple Virtual Machines (VMs) through specific virtualization management software. Each VM runs independently of each other and each VM has its own operating system, applications and virtual hardware environment. The virtual hardware environment includes a virtual CPU, a virtual memory, a virtual storage device, a virtual IO device, and a virtual switch.
The virtual switch of the VM is mainly used to implement data exchange between the VM and an external network and implement data exchange between the VM and another VM. This kind of switch is called a virtual Ethernet switch. The virtual Ethernet switch may be called vSwitch and implemented via software, or may be implemented via hardware, e.g. by using a network card.
The virtual switch may perform Edge Virtual Bridging (EVB), which is an IEEE standard that facilitates the interaction between virtual switching environments and the first layer of the physical switching infrastructure. The EVB vSwitch can provide inbound/outbound communication and inter-VM communication, and aggregate VM traffic as well as provide frame delivery between VMs based on Media Access Protocol (MAC) addresses. Also, the vSwitch may implement the Virtual Edge Port Aggregator (VEPA) standard. VEPA hands all the network traffic generated by the VM to the physical switch connected to the server hosting the VM for processing. Even the traffic among VMs hosted on the same server is processed on the physical switch and returned to the destination VM on the server. The VEPA realizes traffic forwarding among VMs through the physical switch, and also realizes supervision of the traffic of the VMs.